Samenvatting

Encouraging adolescents to participate in physical activity (PA) is crucial for both their immediate and long-term well-being. However, maintaining their engagement remains a challenge. The Health-Promoting School (HPS) model takes a holistic approach by integrating health promotion into education, policies, and the school environment while actively involving students and staff. The research underscores the effectiveness of cocreated interventions in fostering systemic, lasting change. However, empirical studies demonstrating real-world applications and outcomes of these approaches remain limited. This study therefore explores an expanded HPS intervention at a Dutch secondary prevocational school (Echnaton) from 2010 to 2018. It aims to document the design, implementation, and sustainment of this approach while evaluating its impact on the school's health promotion infrastructure, students' PA behaviors, and physical fitness (PF) levels over a period of five years. A mixed-methods evaluation was performed. The qualitative analysis examined policy documents, reports, and semi-structured interviews with involved actors. These data were analyzed using the Action Scales Model (ASM) to track system-level changes across events, structures, goals, and beliefs. The quantitative analysis assessed PA behaviors and PF levels of 840 students over five years through validated questionnaires and fitness tests. Longitudinal changes were determined using Generalized Estimating Equations (GEE). The findings revealed lasting improvements in the school's health promotion infrastructure, realized on all ASM-system levels. Key initiatives included installing water taps, incorporating health education on nutrition and PA, and redesigning the schoolyard to promote PA. These efforts were sustained through active student and staff involvement, a dedicated HPS coordinator, fundraising initiatives, and the integration of health goals into school policies. Physically, students demonstrated significant improvements in fitness measures, including the standing broad jump, bent-arm hang, sit-ups, and grip strength. Screen time decreased significantly. However, no significant positive effects were realized in terms of sports participation or active commuting to school. This case study emphasizes the importance of integrating health promotion into a school's core policies and organizational framework to foster a lasting, supportive environment. It demonstrates the effectiveness of system-wide changes and co-creative approaches over isolated interventions. Future HPS programs should prioritize stakeholder engagement, systemic goal-setting, and sustainable partnerships to promote long-term well-being for both students and staff.